Polylactic Acid Nanofiber Membranes Grafted with Carbon Nanotubes with Enhanced Mechanical and Electrical Properties

Electroconductive materials based on poly(lactic acid)(PLA) electrospinningmembranes grafted with carbon nanotubes (CNTs) functionalized withthe carboxylic group R-COOH have been obtained. PLA electrospunmembranes were modified with sulfuric acid (H2SO4) to oxidize its surface to subsequently graft the CNTs, the treatmenttime and drying of the membranes before grafting with CNTs being critical,influencing the final properties of the materials. SEM images showedthat CNTs presented a uniform distribution on the surface of the PLAnanofibers, while FTIR spectra of PLA-CNTs materials revealed characteristichydroxyl groups, as evidenced by absorption peaks of CNTs. Thanksto the grafting with CNTs, the resulting PLA-CNTs membranes presentan improvement of the mechanical and conductive properties when comparedwith PLA membranes. On the one hand, grafting with CNTs causes thenanofibers to have greater rigidity, so they are more manipulableand can more easily preserve their conformation when stress is exerted.On the other hand, grafting with CNTs allows elimination of the insulatingbarrier of the PLA, reducing the resistivity and providing high electricalconductivity to the PLA-CNTs membranes. The incorporation of CNTsinto PLA electrospun membranes is expected to offer greater functionalitiesto electrospun composite nanofibers for medical and industrial applications.